Active matrix type liquid crystal display devices with thin film transistors to write data on every pixel have been becoming mainstream for liquid crystal display devices. An ordinary active matrix type liquid crystal display device includes a circuit array substrate provided with a plurality of pixel electrodes regularly arranged in the display area, a counter substrate provided with a counter electrode opposite to the pixel electrodes, a liquid crystal layer held between the array and counter substrates, and a sealing material to seal the liquid crystal layer at the periphery of the substrates.
At the edge portion of the array substrate, a transfer pad is provided for supplying a driving voltage to the counter electrode as an electrode-connecting component. A transfer is also provided for electrically connecting the transfer pad to the counter electrode as an electrode transfer component. The driving voltage is supplied from an outside electric power source to the counter electrode through the transfer pad and the transfer.
A voltage supply line is disposed on the array substrate for supplying the driving voltage from the outside electric source to the transfer pad and is also connected to a contact hole formed on the transfer pad. According to a prior art liquid crystal display device, since the contact hole is arranged at the outside of sealing portions, it is exposed to the open air and easily corrodes away. As a result, the voltage supply lines become poor in electrical connection with the contact hole or a predetermined gap is defined between the transfer pad and an insulation layer formed underneath the transfer pad so that bubbles enter the liquid crystal layer and cause troubles such as deteriorations in electrical and/or optical characteristics and a poor picture display.
An object of the present invention is generally to provide a liquid crystal display device with the improvement of corrosion resistance with respect to a contact hole and with that of a good display quality.